An exploration of aqueous oxalic acid production in the coastal marine atmosphere

Organic Aerosol Growth Mechanisms and Their Climate-Forcing Implications

“…The high RH and the presence of fog on 7 August 2003 suggest that most of the aerosol particles on that day contained substantial water. Condensation and volume-limited oxidation during fog events are consistent with the mechanism proposed for oxalic acid formation in cloud droplets (13). The close correspondence between the observed particle-composition size dependence during the fog event and the expected theoretical relationships for condensation (Fig.…”

Ocean-Derived Aerosol and Its Climate Impacts

“…Carbon isotope values for oxalate associated with sub-and supermicrometer particles at Bermuda were similar to d 13 C reported for marine organic material, suggesting a marine source (Turekian et al, 2003). It has been hypothesized that the low molecular weight diacids found in marine aerosol result from the sea-to-air emission of ocean-derived organic matter, including unsaturated fatty acids, followed by photochemical oxidation in the aqueous aerosol phase (Kawamura et al, 1996) or during cloud processing (Crahan et al, 2004). Measurements and models indicate that the likely mechanism for production of oxalic acid in the aqueous phase involves a multistep process initiated by OH oxidation of glyoxal (Carlton et al, 2007;Crahan et al, 2004).…”

Hygroscopic properties of smoke-generated organic aerosol particles emitted in the marine atmosphere

“…On 17 July, the 150 nm particles likely grew out of smaller particles through condensation of VOCs (assuming higher VOC levels on the sunny than on the foggy day), and may therefore have contained higher organic mass fractions than those on 18 July. (ii) Aqueous-phase processing of organics towards more hygroscopic organic species, as has been documented before in the region (e.g., Crahan et al, 2004;Sorooshian et al, 2007). The expected higher O : C ratios resulting from aqueous-phase processing may not be reflected in the bulk measurement of O : C, for the reasons stated above.…”

“…The expected higher O : C ratios resulting from aqueous-phase processing may not be reflected in the bulk measurement of O : C, for the reasons stated above. Filter samples show that two particulate species that are tracers for cloud-processing the region (Crahan et al, 2004;Sorooshian et al, 2007) were observed in PM 10 samples of the smoke on 18 July but not on 17 July: oxalate (236 ng m −3 ) and glyoxylate (79 ng m −3 ). Oxalate is also associated with coarse crustal matter (e.g., Wang et al, 2012); however, its simultaneous detection with glyoxylate only on 18 July suggests that aqueous-phase processing was an important factor on that day.…”

“…An important marine primary organic aerosol source is bubble bursting, which transfers dissolved or film-forming organic substances from the ocean surface into the particle phase in the atmosphere (e.g., Middlebrook et al, 1998;O'Dowd et al, 2004;Cavalli et al, 2004;Leck and Bigg, 2005;Facchini et al, 2008a;Russell et al, 2010;Modini et al, 2010;Ovadnevaite et al, 2011b). Proposed marine sources of SOA include biogenic amines (Facchini et al, 2008b;, isoprene oxidation above phytoplankton blooms (Meskhidze and Nenes, 2006;O'Dowd and de Leeuw, 2007), and aqueous-phase production in marine stratus clouds (Crahan et al, 2004;Sorooshian et al, 2010). In the absence of such sources, marine background aerosol typically shows a hygroscopic mode with growth factors around 1.6-1.79 at 90 % RH (Swietlicki et al, 2008, and references therein).…”